1. Field of the Invention
The invention relates in general to flexible conduit and methods of forming flexible conduit, and in particular to a leak-free flexible conduit.
2. Description of the Related Art
Flexible conduits are presently in wide use in heavy and medium duty truck engine exhaust systems. None, however, are leak free.
A typical automotive engine exhaust system is comprised mainly of steel exhaust pipes and at least one exhaust muffler. The steel exhaust pipes provide a conduit for the engine exhaust to be transferred from the engine exhaust outlet to the muffler and from there to the atmosphere. On heavy and medium duty trucks, for example, mufflers are mounted either on the outside of the driver""s compartment or the frame rail.
Because the engine vibrates, it is necessary to provide a flexible joint in the pipes connecting the engine exhaust outlet to the muffler, which is mounted on either the cab or the frame rail. Employing such a flexible conduit insures against the failure of the steel exhaust pipes. Additionally, a flexible joint in the exhaust pipe connecting the engine to the muffler absorbs the expansion and contraction of the steel pipes, which results from temperature fluctuations.
As described above, a flexible joint is essential to the longevity of the exhaust piping system. However, a flexible joint that is also leak free is essential to a safe driver environment. Exhaust leaking from a joint under the cab or sleeper compartment can enter those compartments and adversely affect the occupants and driver. This has been recognized by Federal Motor Carrier Safety Regulation 393.83(g), which states, in part, that xe2x80x9c[n]o part of the exhaust system shall leak or discharge at a point forward of or directly below the driver/sleeper compartment.xe2x80x9d